There is a need for continuous monitoring of clinical analytes such as lactate, glucose and urea. Sensors for glucose [1] are needed to treat the 300 million worldwide people with diabetes mellitus. But to date, stable, highly accurate and continuous implantable glucose biosensors are not available for the monitoring and treatment of diabetes or any other disease [1]. In vivo measurements of lactate are also important for critical care [2] and metabolic rate determination [3].
A non-invasive device for selective monitoring of physiological fluids and conditions currently does not exist for deployed forces. Unlike civilian use, with popular applications such as glucose monitoring, in-theater, individual combatants require early detection of far more harmful conditions such as dehydration as predicted by lactate levels, or consumption of or exposure to infectious diseases such as malaria. The ability to remotely detect, with a high degree of confidence, the medical status of a serviceperson, stands to dramatically decrease the timeline whereby medical personnel are afforded a more effective way to react.
The disclosed combination of optical microneedles and near-infrared or mid-infrared spectroscopic sensing is original and is a groundbreaking advance for both technologies. Our optical microneedle design is a next step for non-invasive biosampling technology, accommodating MEMS, macroscopic or meso-scale fabrication [4-6]. Recent related developments include miniaturized lactate sensors including thin film electrodes used in catheters and disposable amperometric sensors for on-site analysis [7].